Install mongodb using just shell. No package managers needed.

install-mongodb.sh

set -eux

INSTALLTO="${INSTALLTO:-/opt/mongodb}"
INSTALLED="$(mongo --version 2>/dev/null | sed -n '1{s/.*[^0-9.]\([0-9.]*\)/\1/g;p};q')"
LATEST="${LATEST:-$(curl -s 'http://www.mongodb.org/downloads' | sed -n 's/.*Production Release (\([0-9.]*\)).*/\1/g;ta;b;:a;p')}"
PLATFORM="${PLATFORM:-$(uname | tr A-Z a-z)}"
ARCH="${ARCH:-$(uname -m)}"

if [ "x$INSTALLED" = "x$LATEST" ]
then
  echo "Latest version is already installed"
  exit 0
fi

mkdir -p "$INSTALLTO"
cd "$INSTALLTO"

mkdir downloads
pushd downloads
curl -O http://downloads.mongodb.org/linux/mongodb-${PLATFORM}-${ARCH}-${LATEST}.tgz
popd

mkdir build
pushd build
cat ../downloads/mongodb-${PLATFORM}-${ARCH}-${LATEST}.tgz | gunzip | tar -x
popd
ln -s build/mongodb-${PLATFORM}-${ARCH}-${LATEST}/bin/ bin

mkdir -p /var/mongodb
ln -s /var/mongodb data

sudo apt-get install -y numactl

printf '\n%s\n' 'export PATH="$PATH:'"$INSTALLTO"'/bin"' >> ~/.bashrc

touch "$INSTALLTO"/config.yaml

# start
numactl --interleave=all "$INSTALLTO"/bin/mongod --dbpath "$INSTALLTO"/data --smallfiles --config "$INSTALLTO"/config.yaml